Improvement in preserving wood



To accomplish this result, r

' so mechanically only.

processof tanninghides.

tear scat new cam.

JOSHU A'lhH AYES, or WASHINGTON, nisrnro'r for COLUMBIA.

Letters Patent No. 107,904, dated October 4, 1870.

IMPROV MEN m PRIEISERVING woon.

The Schedule referred to these Letters Patent and making part of the same.

- Be it known that LJOSHUA B. Hayes, M. 1)., of,

Washington city, in the county of Washington and in the District ofGolumbia, have invented certain new and useful Improvements in Rendering Woody Fiber More Durable and Insusceptible to Decay; and do hereby declare that the following is a full, clear,

and exact description thereof.

"rue nature of this invention consists in making wood insusceptibl'e'toi the influence of heat and moisture, and thereby increase itsdurability.

eference should 'be had to the'chemicabnature .of wood, and the effect .of

chemical agents upon its fiber.

Many ways have been suggested to, impregnate the pores of wood with agents that will make it not 'lia- .ble to decay. All of these ways prove ineifectual, forthe reason that the substances employed do not I thoroughly permeate the woodyfiber and pores of the wood, and those. which do act upon the wood do No process is'used to form chemical combinations aviththe fiber oi the wood, by-reason of chemical affinity of the materials used with the woody fiber;

To form a newsubstancc in the wood, as the effect.

of a chemical agentupon the lignine and'cellulose, and thus render the more-delicate structure of the wood durable, is theobject of this invention,

The wood to be treated in .the way prescntly to be described, is placed in an air-tight iron chamber, of sufficient capacity to hold the quantity desired, which chamber is connected, by means of a coduit or pipe, to a retort,- also of suflicient capacity for the purpose.

In this retort I place tannic acid, or any substance containing this acid, as sumac, bark, 8tc., saturated "with sufficient water to" generate steam. I

.When heat is applied to the retort containing this f acid, the steam produced passes "through the conduit or pipe into the air-tight chamber containing the wood, which becomes in a little time impregnatedwith the vapors"containingtannin, which, in the condition of vapor, can be readily understood, permeates thor:

oughly the wood,i drives off surface moisture, and

chemically acts upon the gelatinous, albuniinous, and nitrogenous lignine and cellulose composing the body of the wood,.and.forn1s a substance of .a leathery nature, similar to thatjproduced upon the ships of animals by the use of tannic acid, in the well-known The most characteristic feature tannic acid is that it formsinsolnble compounds with organic matter. It is upon this principle that leather is manufactured. a

When we see thatthe li'gnine and cellulose in wood is .composed of organic matter, gelatinous or albu miuous in nature, the action of tannin upon it, when brought in'contact with it, must produce anew compound in the wood similar tothat of leather. The structure of the wood being thus rendered of aleathery nature its durability must necessarily be increased.

In former times, when mills were run with wooden wheels, it was cnstomary,before gearing said wheels,

.of wood, as those from tar containing carbolic acid,

creosote, 8m, but, as these act only mechanically, no chemical union producing anew substance inrthe wood is had. a

The employment of tannin, or any substance containing this agent, will, however, as before stated, form a chemical union with the'albnminous lignine and cellulose in the wood, and that portion of it is thus rendered of a leathery and insoluble nature,

Again, the heat necessary (equivalent to'superv heated steamito generate vapors containing carbolic acid, creosote, 820., will of itself destroy the delicate fibers of wood, and more injury than .benefit is the result from such impregnation.

In fact,- the employment of superheated steam, (whether from water alone or substances containing ,carbolic acid, &c.,) to dry the wood bydriving off the moisture within it, is of questionable utility, as it must beapp'arent to all comersant'with the structure of the ligninc and cellulose, that these substanare of a delicate nature, incapable of sustaining, without injury, theaction of superheated steam upon them; but, if the lignine and cellulose in the wood, in the first place, be treated in the manner Ihave stated,-thesc delicate structures are rendered insoluble and of a leathery nature, and then the wood, as a second-step, is prepared for the introduction of superhcated steam and antiseptics at a high tempera-- ture, to drive off all moisture and to fill up the pores of the wood without injury to the fiber.

It is a well-known fact in chemistry that while tan nin is by itself soluble in cold water, itis not soluble in boiling water. It is a fact, however, equally well established that tannin is soluble in boiling water with the addition of soda, and is then, as a natural consequence, vaporizable, and, on cooling, separates into .the shape of a powder that is permanent.

that form a chemical union with thelignine and cellulose, rendering them inscluble and of a leathery nature, in. the way I have dcscribed.

, Nor do I make any claim of novelty in the employ r inent of superheated steam to drive off moisture from the wood, as this is a process long in use but What I claim as novel, and desire to secure by Letters Patent, is-- 1. The process of introducing the vapors of tannin, or its equivalent, through the fibers of the wood to be preserved, by means of which a chemical union is effected with the gelatine of the wood, thereby rendering that portionot" the wood of a leathery consistence and, tl'ierefore,-insoluble, in the manner substantially as set forth.

2. The process of subjecting wood to be preserved to the yapors of superheated steam, to drive off 'moisture therefrom, in combination with the vapors of tannin, or its equivalent, when the latter is applied as described, to bring the wood to that condition as to receive the vapors of superheated steam without injury, in the manner substantially as set forth.

3. The process described, of the combination of tannin and superheated steam with tarry compounds, 'to render wood durable and insusceptible to decay, in

the manner substantially as set forth.

In testimony that I claim the foregoing, I have hereunto set my hand this 31st day of July, 1869.

J. R. HAYES, M. D.

Witnesses:

J. L. RIDER, R. F. HUNTER. 

